Biomedical subjects

L Kivisaari

Publications and source records attributed to L Kivisaari.

At least 19 recordsLinked to original sources

PubMed2006

Clinical, radiographic and MRI findings of the temporomandibular joint in patients with different rheumatic diseases.

The aim of this study was to investigate the condition of the temporomandibular joint (TMJ) in patients with different rheumatic diseases, and report correlations between the clinical, radiographic and magnetic resonance imaging (MRI) findings. The 67 patients were divided into four groups: 16 with rheumatoid arthritis (RA), 15 with mixed connective tissue disease (MCTD), 18 with ankylosing spondylitis (AS) and 18 with spondyloarthropathy (SPA). They were clinically examined, and panoramic tomography, lateral panoramic radiography and MRI of the TMJ were performed. MRI showed reduced articular cartilage in 25% (4/16) of RA, 0% (0/15) of MCTD, 17% (3/18) of AS and 17% (3/18) of SPA patients. Condylar changes included erosion, osteophytes and abnormal shape. Disc alterations included perforation, abnormal anterior position and decreased movement. These abnormalities were most frequent in RA patients, and least frequent in MCTD and SPA patients. Crepitation and reduced maximum opening of the mouth correlated with abnormalities of the disc and articular cartilage as shown by MRI. Severe condylar erosion in panoramic tomograms significantly correlated with MRI findings of condylar erosion (P<0.01), diminished thickness of condylar cartilage, abnormal condylar shape, and abnormal shape of the temporal surface of the TMJ (P< or =0.001). The presence of crepitation, limited mandibular movement and/or pain on movement of the jaw often indicated structural damage to the TMJ. Panoramic radiographs provide an alternative method to MRI but, to obtain a more detailed anatomic picture, MRI is recommended for patients with acute unexplained pain or as part of preoperative work up. A panoramic recording is not indicated when MRI is planned.

Adult↗

PubMed2006

Effect of computer-aided detection on mammographic performance: experimental study on readers with different levels of experience.

PURPOSE: To evaluate the effect of computer-aided detection (CAD) on the reader's performance. MATERIAL AND METHODS: Four screening radiologists, two novice radiologists, and two residents with no prior experience in CAD read films of 200 women without and with CAD. The films, including 16 screen-detected cancers and 35 cancers "missed" on prior screening, were divided into two rollers: A (free time schedule) and B (prompted time schedule). Reading times were noted. Individual readings without and with CAD were compared, sensitivities and specificities were calculated. RESULTS: The sensitivity of CAD was 70.6% and specificity 15.8%. In 408 cancer readings, the screeners found 10 and other readers 7 new cancers with the aid of CAD. The screeners changed their opinion four times and others six times from true positive to false negative when CAD was negative. CAD output produced 12 versus 13 new false-positive findings respectively after 2352 readings. CAD did not significantly affect the reader's sensitivities/specificities regardless of the time limit (P = not significant). The use of CAD increased mean time for roller reading from 56 to 63 min (P = 0.053). CONCLUSION: Screening radiologists benefited slightly more from CAD than other readers did, but no statistical significant difference was found in personal readings without and with CAD.

Breast Neoplasms↗

PubMed2006

Impact of the number of readers on mammography interpretation.

PURPOSE: To evaluate the impact of the number of readers on sensitivity and specificity, and compare it with conference consensus reading. MATERIAL AND METHODS: Eight readers read mammography films of 200 women (including 35 false-negative and 16 screen-detected cancers). The sensitivities and specificities of the two methods were calculated: either at least a single cancer-positive opinion within the group (summarized independent reading) or the cancer-positive opinion of the reader majority (conference consensus reading) was considered decisive. RESULTS: The mean sensitivity for summarized independent readings of different groups was 64.7% as compared to the 43.1% mean sensitivity of conference consensus readings. The mean specificities were 92.4% and 97.7%, respectively. The greatest sensitivity of 74.5% was achieved when the readings of the four best-performing readers were combined. CONCLUSION: The sensitivity of reading is maximal when any positive opinion within a pair or a group of readers is taken into consideration. Discordant double reading may best be judged as screening positive, and the value of a third opinion should be questioned.

Breast Neoplasms↗

PubMed2004

Scoring CT/HRCT findings among asbestos-exposed workers: effects of patient's age, body mass index and common laboratory test results.

We studied the effects of age, body mass index (BMI) and some common laboratory test results on several pulmonary CT/HRCT signs. Five hundred twenty-eight construction workers (age 38-80, mean 63 years) were imaged with spiral and high resolution CT. Images were scored by three radiologists for solitary pulmonary nodules, signs indicative of fibrosis and emphysema, ground glass opacities, bronchial wall thickness and bronchiectasis. Multivariate statistical analyses were adjusted for smoking and asbestos exposure. Increasing age, blood haemoglobin value and erythrocyte sedimentation rate correlated positively with several HRCT signs. Increasing BMI was associated with a decrease in several signs, especially parenchymal bands, honeycombing, all kinds of emphysema and bronchiectasis. The latter finding might be due to the suboptimal image quality in obese individuals, which may cause suspicious findings to be overlooked. Background data, including patient's age and body constitution, should be considered when CT/HRCT images are interpreted.

Adult↗

PubMed2004

Lumbosacral radiographic signs in patients with previous enteroarthritis or uroarthritis.

OBJECTIVE: To investigate if there are differences in radiological findings in lumbosacral spine radiographs between different subgroups of patients with previous reactive arthritis. METHODS: 95 patients with previous enteroarthritis (n = 53), uroarthritis (n = 37), or Reiter's syndrome, aetiology unknown (n = 5) were included in the study. Lumbosacral radiographs were taken 7 to 38 years after the initial arthritis. Three independent observers read the radiographs. Spinal changes included squaring of vertebrae, Romanus lesions, syndesmophytes, and osteophytes. Sacroiliitis was recorded according to the New York and Stoke methods. Signs of enthesitis in the iliac crest and disc space narrowing were recorded. Interobserver reliability and intraobserver reproducibility were determined. RESULTS: 23% of patients had grade 2-4 sacroiliitis (New York criteria) and 14% had syndesmophytes. There was more frequent sacroiliitis (32% v 13%) in uroarthritis than in enteroarthritis, and more syndesmophytes (mean 0.54 v 0.15 per patient; prevalence 24% v 6%, respectively). In other radiological features, no significant differences were present between the groups. In the material as a whole, patients with sacroiliitis of grade 2 or more had significantly less disc space narrowing both in patient comparisons (chi(2) test) and in numbers of spaces involved (Mann-Whitney test). Interobserver and intraobserver agreement, calculated using Cohen's kappa method, varied from 0.2 to 1. CONCLUSIONS: Syndesmophytes and sacroiliitis are more common in patients with previous uroarthritis than in those with previous enteroarthritis, but radiological findings in lumbosacral spine radiographs are characteristically similar.

Adult↗

PubMed2004

Liver tumour MRI: what do we need for lesion characterization?

BACKGROUND: Hepatic lesions constitute a daily challenge to radiology in clinical settings, and non-invasive methods are valuable in the characterization of these liver tumours. We undertook our investigation to assess the lesion characterization potential of MRI by evaluating several unenhanced MR sequences and the dynamic gadolinium (Gd)-enhanced technique. METHODS: A total of 116 focal liver lesions in 116 patients were included in our retrospective study, and histological verification was available for 107 lesions. Nine haemangiomas had a follow-up of 2 years. The 1.5-T MR system was used. T1- and T2-weighted sequences and dynamic Gd-enhanced studies were evaluated by two individual readers as separate sequences and also collectively. Lesions were classified into benign or malignant, and a specific diagnosis was proposed. The McNemar test was used in statistical analysis, and interobserver variation was measured using kappa statistics. RESULTS: Lesion classification into benign and malignant tumours (by evaluating all images in concert) was assessed in 83% and 89% of cases by readers 1 and 2, respectively. From single sequences, best lesion classification was achieved with Gd-enhanced T1 by both readers. The difference in classification was statistically significant when all sequences were evaluated in comparison with any single sequence alone (P = 0.02). Specific diagnosis was correctly determined using all sequences together in 60% and 71% of cases by readers 1 and 2, respectively. For individual sequences, correct diagnosis was most frequently proposed with a Gd-enhanced T1-weighted sequence by both readers (59% and 65% for readers 1 and 2, respectively). CONCLUSION: Multisequential MRI using Gd-enhanced imaging performs extremely well in liver lesion classification, and with moderate ability to determine a specific diagnosis.

Adult↗

PubMed2004

HLA-DRB1* alleles and temporomandibular joint erosion in patients with various rheumatic diseases.

OBJECTIVE: To investigate the association between HLA antigens and temporomandibular joint (TMJ) erosion, salivary composition, and focal sialadenitis in patients with rheumatic diseases. METHODS: Eighty-four patients, 24 with rheumatoid arthritis (RA), 19 with mixed connective tissue disease (MCTD), 19 with ankylosing spondylitis (AS), and 22 with spondyloarthropathy (SPA) were studied. Each patient underwent clinical examination of the masticatory system, unstimulated and stimulated saliva collection, and minor salivary gland biopsy. Radiographs (OPTG) of the TMJ were obtained, and HLA allele (A, B, C and DRB1*) analysis was performed. Erosion in OPTG was scored from 0 (no erosion) to 4 (condyles totally eroded). In the analysis, scores 0-2 were grouped as normal or mild changes, and scores 3-4 as distinct erosions. One hundred healthy blood donors served as controls for HLA typing. RESULTS: Distinct erosion of the TMJ in OPTG was observed in 22 (27%) patients. It affected four (17%) of the 24 patients with RA, three (17%) of the 18 with MCTD, seven (37%) of the 19 patients with AS and eight (38%) of the 21 with SPA non-significant (NS). The mean erosion scores were 1.7 for RA, 1.3 for MCTD, 2.5 for SPA, and 1.6 for AS patients [probability (p) = 0.04]. The frequency of HLA-B27 antigen was higher in the AS and SPA patients, and that of HLA-DRB1*04 allele higher in RA patients than in control subjects. In the whole patient population, HLA-DRB1*01 allele was significantly associated with erosions 16/36 (44%) versus 6/46 (131%1) (p = 0.0014). In the SPA group, patients with HLA-DRBI*01 allele had a significantly higher occurrence of distinct erosions than patients without this allele [8/10 (80%) versus 0/11 (0%) (p = 0.0002)], whereas DRB1*06 was protective [0/8 (0%) versus 8/13 (62%) (p = 0.018)]. HLA-DRB1*04 was associated with increased salivary IgG in the RA patients. CONCLUSION: HLA antigens are significantly associated with the development of destructive lesions in the TMJ, as well as composition of saliva in patients with various rheumatic diseases.

Alleles↗

PubMed2004

Factors associated with nonunion in conservatively-treated type-II fractures of the odontoid process.

In type-II fractures of the odontoid process, the treatment is either conservative in a halo vest or primary surgical stabilisation. Since nonunion, requiring prolonged immobilisation or late surgery, is common in patients treated in a halo vest, the identification of those in whom this treatment is likely to fail is important. We reviewed the data of 69 patients with acute type-II fractures of the odontoid process treated in a halo vest. The mean follow-up was 12 months. Conservative treatment was successful, resulting in bony union in 32 (46%) patients. Anterior dislocation, gender and age were unrelated to nonunion. However, nonunion did correlate with a fracture gap (> 1 mm), posterior displacement (> 5 mm), delayed start of treatment (> 4 days) and posterior redisplacement (> 2 mm). We conclude that patients presenting with these risk factors are unlikely to achieve bony union by treatment in a halo vest. They deserve careful attention during the follow-up period and should also be considered as candidates for primary surgical stabilisation.

Adolescent↗

PubMed2003

Effects of tobacco smoking on findings in chest computed tomography among asbestos-exposed workers.

This study examined the effects of smoking on the findings in chest computed tomography (CT) in 587 asbestos-exposed construction workers (11 females, 576 males, mean age 62 yrs; 18 never-smokers, 406 exsmokers and 163 current smokers). The workers were imaged with spiral CT and high-resolution CT. A total of 13 radiological signs were scored by three radiologists independently. The workers' medical data, smoking habits and occupational exposures were collected at an interview. The effects of smoking status and smoked pack-yrs (0-87.5) on the CT signs were studied using multivariate analysis adjusted for confounding factors. Smoking increased all emphysema signs and contributed to bronchial wall thickening. Smoking was negatively associated with curvilinear and septal lines as well as with parenchymal bands. In persons who had smoked <10 pack-yrs, smoking was positively related to paraseptal emphysema and to bronchial wall thickening and negatively related to septal lines, subpleural nodules and honeycombing. Smoking was related to several abnormal computed tomography signs even among those with relatively small exposure. Computed tomography can detect changes due to smoking at an early stage.

Aged↗

PubMed2002

Computed tomography of asbestos-related pleural abnormalities.

OBJECTIVES: To study the observer agreement in several asbestos-related pleural abnormalities and to define criteria to discriminate between pleural changes in workers with occupational disease, and those in controls. METHODS: Pleural abnormalities in spiral computed tomography of 602 construction workers with asbestosis or bilateral pleural plaques and 49 controls were reviewed by three radiologists using structured forms. RESULTS: Intra- and inter-observer agreement (weighted kappa) was 0.4 or better with regard to the calcification, extent and thickness of pleural disease. These factors all correlated positively with the duration of asbestos exposure. There were significant differences in these pleural changes between the workers (mean extent per side 83 cm(2)) and controls (mean extent per side 40 cm(2)). Of the controls, 84% showed pleural lesions with an estimated extent of 10 cm(2) or more, bilateral in 64%. The extent of 45 cm(2) in pleural disease was the best value for discriminating between the controls and diseased workers, with a sensitivity of 82% and a specificity of 66%. The degree of pleural calcification, however, was the best discriminator between these groups, but quantitative methods are necessary for its use in the diagnostics of individuals. CONCLUSIONS: The extent, calcification and thickness were well-repeatable indicators of benign pleural pathology and thus their use in future classification systems in computed tomography is recommended. In our material, the extent of 45 cm(2) and the degree of calcification were helpful in discriminating between pleural changes in workers with occupational disease, and those in controls who also presented marked pleural pathology.

Adult↗

PubMed2001

MRI abnormalities of foot and ankle in asymptomatic, physically active individuals.

OBJECTIVE: To assess MRI changes in the ankle and foot after physical exercise. DESIGN AND PATIENTS: Nineteen non-professional marathon runners and 19 age- and sex-matched controls volunteered for the study. All had ankle and foot MR images (1.5 T) taken in three perpendicular planes (STIR, T2F and T1FS sequences) within 3 h of running a full-length marathon (42.125 km). Three radiologists independently analysed the groups on a masked basis using a predefined form. RESULTS: Severe bone marrow oedema was seen in one and slight bone marrow oedema in three marathon runners. Slight bone marrow oedema was found in three control subjects. Signal alteration within the soleus muscle, consistent with a grade 1 strain, was found in one marathon runner. Small punctate hyperintensities within the Achilles tendon were seen in 26% of the marathon runners and in 63% of controls (P = 0.016). An increased amount of fluid in the retrocalcaneal bursa was found in one control and in none of the marathon runners. Small amounts of fluid in the retrocalcaneal bursa were seen in 68% of marathon runners and in 53% of controls. Grade 1 or 2 peritendinous joint fluid was found around 22% of tendons, among both marathon runners and controls, most often involving the tendon sheath of the flexor hallucis longus muscle. An increased amount of joint fluid was noted in 34% of the joints of the marathon runners, and in 18% of the controls. CONCLUSION: MRI shows several abnormalities in the ankle and foot both after marathon races and in asymptomatic physically active individuals without any preceding extraordinary strain. Recreational sports may lead to a number of positive MRI findings without correlation with clinical findings.

Adult↗

PubMed2001

Acute paediatric ankle trauma: MRI versus plain radiography.

OBJECTIVE: To evaluate the diagnosis of acute physeal ankle fractures on plain radiographs using MRI as the gold standard. METHODS: Sixty consecutive children, 29 with a clinical diagnosis of lateral ligament injury and 31 with physeal ankle fractures, were examined using both radiographs and MRI in the acute period. The imaging data were reviewed by three "masked" radiologists. The fracture diagnosis and Slater-Harris classification of radiographs were compared with findings on MRI. RESULTS: Plain radiography produced five of 28 (18%) false negative and 12 of 92 (13%) false positive fracture diagnoses compared with MRI. Six of the 12 false positive fractures were due to a misclassification of lateral ligament disruption as SH1 fractures, Altogether a difference was found in 21% of cases in either the diagnosis or the classification of the fractures according to Salter-Harris. All bone bruises in the distal tibia and fibula and 64% of bone bruises in the talus were seen in association with lateral ligament injuries. Talar bone bruises in association with fractures occurred on the same side as the malleolar fracture; talar bone bruises in association with lateral ligament disruption were seen in different locations. The errors identified on radiographs by MRI did not affect the management of the injury. CONCLUSIONS: The incidence of false negative ankle fractures in plain radiographs was small and no complex ankle fractures were missed on radiographs. The total extent of complex fractures was, however, not always obvious on radiographs. In an unselected series of relatively mild ankle injuries, we were unable to show a single case where the treatment or prognosis based on plain radiography should have been significantly altered after having done a routine MRI examination. Plain radiography is still the diagnostic cornerstone of paediatric ankle injuries.

Acute Disease↗

PubMed2001

Endorectal magnetic resonance imaging of prostatic cancer: comparison between fat-suppressed T2-weighted fast spin echo and three-dimensional dual-echo, steady-state sequences.

The aim of this study was to develop an endorectal MRI strategy for prostatic cancer. We evaluated the MR images from 44 consecutive prostatic cancer patients treated by radical prostatectomy. Each sequence from every examination was assessed separately with a specific tumor map drawn. Tumor localization, capsular penetration, and seminal vesicle invasion were marked on maps on the basis of T2 and DESS (dual-echo steady-state) sequences. Thirty patients also had T1-weighted images, and these were assessed with regard to possible tumor outgrowth. The maps were compared with histopathological findings from radical prostatectomy specimens. According to our study, DESS equaled T2 in every respect. No statistically significant differences between the sequences were found with respect to detecting either tumor localization, outgrowth, or seminal vesicle invasion. DESS is a potential new sequence in prostatic MRI as it has been proven to parallel the routinely used T2-weighted imaging.

Aged↗

PubMed2001

Pancreatic carcinoma and fast MR imaging: technical considerations for signal intensity difference measurements.

The aim of the study was to find the fast magnetic resonance imaging (MRI) sequence with the best conspicuity of pancreatic lesions at 1.0 T and 1.5 T. A total of 51 patients were studied. At 1.0 T, 22 patients with verified malignant pancreatic lesions were studied using the T1-weighted breath-hold spoiled Gradient Echo 2D FLASH(75) or FLASH(80) sequences, both non-enhanced and enhanced with gadolinium. The relative signal intensity difference (SIDR) between lesion and pancreas was measured. At 1.5 T, 20 patients with primary malignant lesions of the pancreas, and nine patients with 13 benign cystic lesions were examined with the breath-hold T2-weighted TrueFISP, HASTE, T1-weighted 2D FLASH(80) and FLASH(50) fat saturation sequences, the latter also enhanced. The signal intensity (SI) values of the pancreas and lesions as well as the pancreatic standard deviation (S.D.) were assessed, and the contrast-to-noise ratio (C/N) was determined. Statistical significances were calculated using an analysis of variance. No statistically significant difference between the sequences used in the conspicuity of cancer was found, either at 1.0 T or at 1.5 T. At 1.5 T, the T2-weighted TrueFISP and HASTE sequences could differentiate benign, cystic lesions from malignant lesions.

Adult↗

PubMed2001

Optimal timing of post-biopsy MR imaging of the prostate.

PURPOSE: To assess the quantity and frequency of hemorrhage after prostatic biopsy. As post-biopsy blood products may interfere with interpretation of MR images, we also investigated the optimal timing for MR examination after biopsy. MATERIAL AND METHODS: Fifteen patients scheduled for prostatic biopsies were imaged with endorectal MR before and after the procedure. In addition, MR studies of 42 patients with prostate cancer were retrospectively analyzed. The amount of post-biopsy blood product and the degree of its interference with image interpretation were assessed. RESULTS: Of a total of 57 patients, 44 (77%) had visible post-biopsy hemorrhage. However, the presence of blood products were considered to interfere with interpretation of the images in only 12 (21%) cases. This disturbing effect seems to diminish after 21 days from biopsy. The total amount of blood clearly decreased after 28 days. CONCLUSION: Deferring MR imaging for at least 3 weeks after prostatic biopsy is advisable. T1-weighted images are necessary to rule out false-positive findings caused by post-biopsy hemorrhage.

Aged↗

PubMed2001

Estimation or quantification of tumour volume? CT study on irregular phantoms.

PURPOSE: To compare radiologists' subjective size estimation to computerised volume quantification of tumour-like phantoms in spiral CT. MATERIAL AND METHODS: Eight tubular phantoms with the inside irregularly covered with silicone (8.7-31.6 ml) were imaged. The phantoms were pairwise compared to analyse the differences in silicone volumes. The observers, 2 radiologists and 2 residents, used both subjective image analysis (2 sessions) and computerised volume quantification (1 session). Accuracy and observer agreement of both methods were calculated. RESULTS: Subjective size estimation was correct in 51% (mean weighted kappa, Kqw=0.73). Using four observers' mean value (Kqw=0.81) or median value (Kqw=0.77) slightly improved the results. Average intra-observer agreement was better than average interobserver agreement. In computerised volume quantification 70% of all classifications were correct (mean Kqw=0.85). The results were moderate even when every second or fourth slice were measured. CONCLUSION: Subjective size estimation of irregular tumours should be repeatedly performed by the same observer, or by using the mean or median estimate of several observers. Computer-based methods are even more reliable and their use is especially recommended for film readers with limited radiological experience. Only every fourth slice may be measured without a major loss of measurement accuracy.

Humans↗

PubMed2001

Prostatic MR imaging. Accuracy in differentiating cancer from other prostatic disorders.

PURPOSE: We assessed the accuracy of MR imaging in differentiating between cancer and other prostatic disorders, and evaluated the diagnostic criteria for various prostatic diseases. MATERIAL AND METHODS: A total of 74 endorectal coil MR studies were performed on 72 patients. Twenty patients had prostatic cancer, 20 benign prostatic hyperplasia (BPH), 4 acute bacterial prostatitis, 5 chronic bacterial prostatitis (2 also belonging to the previous category), 19 chronic non-bacterial prostatitis/chronic pelvic pain syndrome, and 6 were symptomless voluntary controls. All studies were interpreted by two experienced radiologists in random order. Radiologists were blinded to all clinical data including the age of the patients. Based on MR findings, both radiologists filled in a form covering diagnostic criteria and diagnosis. RESULTS: Accuracy in diagnosing prostate cancer was 74%. Sensitivity was 50% and specificity 83%, and positive and negative predictive values were 53 and 82%, respectively. Bacterial prostatitis showed some features similar to carcinoma. Abundant BPH rendered cancer detection more difficult. No diagnostic criterion was clearly better than the others. Interobserver agreement on the MR diagnosis ranged from moderate to good. CONCLUSION: Without knowledge of accurate clinical data, MR seems to be too insensitive in detecting prostate cancer to be used as a primary diagnostic tool.

Aged↗

PubMed2001

Evaluation of pleural disease using MR and CT. With special reference to malignant pleural mesothelioma.

PURPOSE: To evaluate MR imaging and CT in differentiating malignant pleural mesothelioma from other malignancies or benign pleural disease. MATERIAL AND METHODS: Thirty-four patients (18 pleural mesotheliomas, 9 other malignancies, 7 benign pleural diseases) were examined using enhanced CT and MR. Two radiologists reviewed the CT and two others the MR images. Comparisons were made between the diagnostic groups and the imaging methods. RESULTS: The abnormalities commonly found in malignant disease, but significantly less frequently in benign pleural disease, were focal thickening and enhancement of interlobar fissures. In mesothelioma, enhancement of interlobar fissures, tumour invasion of the diaphragm, mediastinal soft tissue or chest wall, were significantly more often observed than in other malignancies and MR was the most sensitive method. In other malignancies, invasion of bony structures was a more common finding and was also better shown by MR. The contrast-enhanced T1 fat-suppressed (CET1fs) sequence detected these features better than other MR sequences. CONCLUSION: MR, especially the CET1fs sequence in three planes, gave more information than enhanced CT. Focal thickening and enhancement of interlobar fissures were early abnormalities indicating malignant pleural disease. MR could be clinically useful for differentiating mesothelioma from other pleural diseases.

Adult↗